For conducting such a mass change, it is generally known in the art of coating machines in the confectionary industry to heat up the coating machine with the previously processed mass and to empty the coating machine by discharging the previously processed mass by a return pump. After having pumped off the previously processes mass, the interior of the coating machine and the aggregates being arranged therein are mechanically cleaned as far as they are accessible. This means that remainders of the mass are manually removed by a tool, for example by a flat trowel. This cleaning process takes a lot of time, and depending on the accessibility of the interior, it may be very exhausting for the staff. Furthermore, the coating machine is only pre-cleaned to some extent such that a second cleaning step is required. During this second cleaning step, either water or cocoa butter is used. It is known to clean coating machines with water. For this purpose, a commonly available handheld pressure washing device is used while the coating machine is not operated. The pressure washing device includes a nozzle through which water is sprayed onto the aggregates of the coating machine. The remainders of the mass sticking to the aggregates are removed due to the pressure of the applied water. This cleaning step practically also is a mechanical method, and it is only successful as far as the aggregates are accessible. The water being sprayed by the pressure washing device is hot, but it cools down comparatively quickly after having left the nozzle, and in summary it is not capable of substantially heating up the aggregates and elements of the coating machine. Places of the coating machine which are hard to be accessed, for example the bottom side of shafts, bars and the like, are only partly reached, and they are thus not sufficiently cleaned. Due to the spraying of water with pressure, the mass to be removed is also distributed onto other aggregates of the coating machine and into places which are not accessible. The use of water also requires drying afterwards. Furthermore, it is a drawback that the water consumption of the pressure washing device is respectively high since the water being applied by spraying flows out off the coating machine and thus cannot be reused. Accordingly, a water discharge needs to be located below the coating machine. The use of a pressure washing device requires that it is continuously fed with heated water such that respectively high energy consumption is unpreventable. The cleaning staff who manually conducts the cleaning operation has to be protected from the rebounding water by respective clothing and safety goggles. This way of pressure washing is also disadvantageous in the sense of reducing the lifetime of bearings of shafts and other aggregates of the coating machine since the lubricant being contained in the bearings is at least partly removed by the pressurized water.
To counteract these drawbacks of the known handheld pressure washing device operating with water, it is also known in the art of coating machines in the confectionary industry to introduce a washing mass, for example cocoa butter or a different fat solution, into the coating machine. The coating machine is then started without articles passing through it such that the washing mass is continuously circulated, and it flows through a coating station, for example. In this way, the washing mass reaches a substantial portion of the elements of the coating machine being soiled with the previously processed mass, and these parts are more or less cleaned by melting the mass. However, not all elements of the coating machine are reached by the washing mass such that the cleaning effect is not perfect. At the end of the cleaning process of the coating machine, the washing mass is removed from the coating machine, and it may be further processed in the normal chocolate production. In the following, the new coating mass may be introduced.
Furthermore, it is known in the art of coating machines in the confectionary industry to design substantial elements of the coating machine to be made of stainless steel and to conduct wet cleaning using hot water under pressure after having removed the previous mass from the coating machine. Such a wet cleaning operation has various drawbacks. When applying a spraying jet of hot water onto the grating belt, there is a substantial spraying and distribution effect such that the aggregates being located below the upper part of the grating belt are only reached to a small extent. Due to the hot water necessarily being introduced into the coating machine, there is a contamination which results in increased growth of bacteria. To counteract this danger, it is known to conduct a drying operation after the cleaning operation with hot water, the drying operation using a jet of hot air. The elements of the machine are heated in this way, and the drying operation needs to be conducted over a respectively long period of time. However, not all parts are actually dried, and it is not possible to check whether or not all elements which had been contacted by hot water have actually been dried.
For a mass change to be conducted in a coating machine, it is also generally known in the art of coating machines in the confectionary industry to cut open the grating belt in a direction transverse to its moving direction and to open the loop formed by the grating belt in this way such that the aggregates being located below the upper part of the grating belt are accessible for cleaning. Once again, washing masses are used for cleaning. The washing masses may be cocoa butter or hot water, for example. Accordingly, cleaning is comparatively complicated, complex and insecure. Especially, the cut open grating belt has to be reassembled after cleaning which takes a substantial period of time.
A method for cleaning a coating machine and a cleanable coating machine are known from German Patent Application No. DE 198 48 766 A1 corresponding to U.S. Pat. No. 6,348,105 B1. The known coating machine includes a frame and a grating belt serving to support the articles to be coated. The grating belt is arranged within the frame to be rotatingly driven therein. The grating belt is guided by deflecting elements. A tub including a heatable double casing is located below the grating belt. The tub is also located below all common aggregates such as a bottom wall station including a dipping box and a vibrating apparatus. Such a coating machine usually includes side walls which are covered by cover sheets at their upper ends. The working width of the coating machine is realized between the side walls as it corresponds to the grating belt width. A roof structure is located above the grating belt plane. The structure continuously extends over the entire length and width of the coating machine in a roof-like configuration. A curtain box, a fan for blowing off surplus mass from the articles being located on the grating belt and possibly additional elements, such as a control unit and the like, are located in the region of the structure. For cleaning such a coating machine, water is filled into the tub, the water having a temperature above the melting temperature of the coating mass. The water is applied onto the aggregates to be cleaned by one or more pumps and one or more hoses in substantially pressureless circulation. The washing water circulates within the circuit with no pressure, and it is directed onto the aggregates to be cleaned in a washing process, the mass being located at these aggregates being melted. The temperature of the coating machine is maintained by the heated double casing. The distribution of the hot water is realized by hand depending on the degree of pollution of the respective aggregates. The remainders of the mass sticking to the aggregates are being melted, and they reach the water in their melted condition, the water being circulated, meaning the usually used discharge of the tub is closed during the cleaning operation. The cleaning and washing operation is conducted until substantial cleaning has been achieved. The period of time during which the washing and cleaning operation is realized depends on experience values which may also depend on the mass. Efficiency of the known cleaning process and its duration strongly depend on how carefully the staff manually operates the washing and cleaning process. The most important aggregates to be cleaned are driven during the washing and cleaning process. After the washing and cleaning process has been completed, a drying process may be conducted. During the drying process, the double casing is still heated and the fan of the coating machine is used for blowing air onto the aggregates and through the grating belt.
Another coating machine is known from German Patent No. DE 42 43 814 C1 corresponding to U.S. Pat. No. 5,437,723. The machine elements of the known coating machine are cleaned during a mass change by a washing mass at increased safety and improved accessibility of the aggregates being located below the upper part of the coating machine. For this purpose, the known coating machine includes a tensioning device having an increased tensioning path allowing for lifting of the grating belt. The coating machine includes elements for supporting the lifted grating belt. Especially, these elements are designed as supports for supporting carriers being arranged at the frame of the coating machine. In this way, the grating belt is designed to be lifted and to be supported in its lifted position, especially by supports and carriers, such that the aggregates being located below the upper part of the grating belt may be directly accessed for cleaning with a washing mass such that cleaning is easier, simpler and faster at increased safety. For example, the aggregates located below the upper part of the grating belt may be a vibrating device, a bottom wall station, a bottom roller and the like. Thus, the grating belt is designed to be lifted in a way that the aggregates being located below the lifted grating belt are freely accessible from the side. In the lifted position, there is a distance of approximately 20 cm to 30 cm between the lifted part of the grating belt and the surface of the aggregates such that the washing mass may be directly directed on to the aggregates to be cleaned by nozzles without spraying effects occurring at the grating belt. On the other hand, it is especially preferred to use cocoa butter instead of hot water as the washing mass to counteract the danger of contamination.